Many changes.

lib/api/controllers/collections/postCollection.ts

@@ -0,0 +1,56 @@
+import type { NextApiRequest, NextApiResponse } from "next";
+import { prisma } from "@/lib/api/db";
+import { Session } from "next-auth";
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse,
+  session: Session
+) {
+  if (!session?.user?.email) {
+    return res.status(401).json({ response: "You must be logged in." });
+  }
+
+  const email: string = session.user.email;
+  const collectionName: string = req?.body?.collectionName;
+
+  if (!collectionName) {
+    return res
+      .status(401)
+      .json({ response: "Please enter a valid name for the collection." });
+  }
+
+  const findCollection = await prisma.user.findFirst({
+    where: {
+      email,
+    },
+    select: {
+      collections: {
+        where: {
+          name: collectionName,
+        },
+      },
+    },
+  });
+
+  const checkIfCollectionExists = findCollection?.collections[0];
+
+  if (checkIfCollectionExists) {
+    return res.status(400).json({ response: "Collection already exists." });
+  }
+
+  const createCollection = await prisma.collection.create({
+    data: {
+      owner: {
+        connect: {
+          id: session.user.id,
+        },
+      },
+      name: collectionName,
+    },
+  });
+
+  return res.status(200).json({
+    response: createCollection,
+  });
+}